To use valueFrom, StepInputExpressionRequirement must
be specified in the workflow or workflow step requirements.
If valueFrom is a constant string value, use this as the value for
this input parameter.
If valueFrom is a parameter reference or expression, it must be
evaluated to yield the actual value to be assiged to the input field.
The self value in the parameter reference or expression must be
1. null if there is no source field
2. the value of the parameter(s) specified in the source field when this
workflow input parameter **is not** specified in this workflow step's scatter field.
3. an element of the parameter specified in the source field when this workflow input
parameter **is** specified in this workflow step's scatter field.
The value of inputs in the parameter reference or expression must be
the input object to the workflow step after assigning the source
values, applying default, and then scattering. The order of
evaluating valueFrom among step input parameters is undefined and the
result of evaluating valueFrom on a parameter must not be visible to
evaluation of valueFrom on other parameters.
To use valueFrom, StepInputExpressionRequirement must be specified in the workflow or workflow step requirements. If valueFrom is a constant string value, use this as the value for this input parameter. If valueFrom is a parameter reference or expression, it must be evaluated to yield the actual value to be assiged to the input field. The self value in the parameter reference or expression must be 1. null if there is no source field 2. the value of the parameter(s) specified in the source field when this workflow input parameter **is not** specified in this workflow step's scatter field. 3. an element of the parameter specified in the source field when this workflow input parameter **is** specified in this workflow step's scatter field. The value of inputs in the parameter reference or expression must be the input object to the workflow step after assigning the source values, applying default, and then scattering. The order of evaluating valueFrom among step input parameters is undefined and the result of evaluating valueFrom on a parameter must not be visible to evaluation of valueFrom on other parameters.